Labyrinth seals of a gas turbine engine are often used as air-oil seals to provide sealing of rotating shafts of bearing compartments and gear cases, etc. Labyrinth seals typically comprise knife edges or teeth or fins which rotate relative to a surrounding seal land or runner, the knife edges having tight tip clearances with a surface of the land or runner. The relative rotation between the knife edges and the runner of labyrinth seals, however, can tend to cause knife edge wear which can significantly reduce the sealing capability.
Labyrinth seals are life limited parts that are not repairable and are therefore generally not attached to high cost parts such as impellers or rotors. Instead they are components in and of themselves. Separate labyrinth seals require additional part count per engine, and additional cost due to extra machining of mating parts.
Accordingly, there is a need to provide a repairable labyrinth seal that addresses at least some of the above issues.